Caption: Demonstration of ultrasonic levitation, showing an oscilloscope display of the standing ultrasound wave being used to make polystyrene balls levitate above a loudspeaker. The wave is shown collapsing, with the polystyrene balls falling to the ground. Ultrasonic levitation is being developed to help grow tissue cultures and for other biomedical applications. The system comprises a loudspeaker that emits high-frequency ultrasound, and a reflector. By precisely controlling the sound a stable standing wave can be formed in the cavity. This wave has fixed regions of low and high pressure, and in specific regions the force of the wave balances gravity, holding the balls aloft. This system is being designed for culturing human cells and tissues, such as cartilage, which can be grown surrounded by culture medium. The shape of the growing tissue can be precisely controlled by varying the sound. This helps to grow implants and grafts tailored exactly for their intended location. Filmed at the University of Southampton, UK, in 2016.